Integrated circuit (IC) chips are ubiquitously used in electronic devices, for example portable or handheld devices, computers, appliances, vehicle control systems, watches, and many others. IC chips are generally fabricated on silicon wafers and packaged so that they can be incorporated into circuitry of the electronic device. Circuits may be laid out on printed circuit boards (PCBs) and circuit components, for example IC chips, may be mounted to the PCB using any conventional mount techniques, for example surface mount technology, selective soldering, and pin-in-hole reflow. The circuit components (e.g. IC chips) may be connected on the PCB using conductive traces, typically copper traces.
PCBs may vary in complexity from simple single and double-layer circuit boards to more complex multi-layer boards. Multi-layer boards are typically made of layers of an insulating substrate material, such as fiberglass reinforced epoxy, which are interleaved with signal layers that include traces connecting PCB-mounted components to other components. In multi-layer PCBs, it is generally known to route electrical signals from one layer to another layer by through-holes, or vias. Vias are holes which extend through one or more of the layers of the PCB. Vias are typically internally lined with conductive material for electrically coupling traces and/or mounting contacts to other PCB layers. The top surface of the PCB typically includes electrical contacts to which terminals of the IC chip (interchangeably referred to herein as IC package) may be connected. The PCB typically also includes one or more ground and power planes.
With the advance of technology and increasing complexity of electronic devices, such as portable devices, the IC chips and circuitry connecting those chips have become more complex and correspondingly may generate increased amounts of heat. Improved methods and systems for thermal management may be needed. While certain advancements in active cooling have been achieved, conventional techniques for passive cooling may be deficient in many regards. Examples of certain improved techniques and systems, which may provide improvement over currently known techniques for passive thermal management of printed circuit boards, are described herein.